Hey guys, what about using pure castor oil as afterrun? I already use a castor-based fuel in all of my engines, and was thinking that pure castor should be good for use as after-run. What about it? Pros, cons?
Thanks...

It is probably fine. But if you leave your engine for a long time (like two years) the castor tends to gum up and stick the piston inside the cylinder. I use automatic transmission fluid.

I've never used after run oil of any type. In 20 years, I've only had a problem once. When I left my Como .51 in the car trunk on a warm, damp summer night, the bearings rusted immediately.

Dr.1

The absolute longest any of my engines ever go without being ran is a couple of months. I make a point to fly planes that I haven't flown in a while if I can't remember flying them in the past couple of months! I'm thinking of trying it to see. However, I bought some tonight at walmart (medicinal grade) and it's pretty expensive. Two bucks for a little bottle. ATF would definitely be cheaper. I've used ATF before, but I was just looking for something more "natural,"--something that lubes the engine all the time anyway!

Another thing to mention--my planes stay in a trailer, and so get cold in the winter. Would the cold accelerate the "gumming up" effect?

Yeah, ATF, or Marvel Mystery Oil, or even any automotive synthetic oil works just great and probably ends up being much cheaper because you buy each by the quart.

DS.

In very cold weather, castor oil turns waxy (it literally becomes a solid), but it returns to the liquid state when things warm up. If you use castor as after-run oil & store it outside, then want to use the engine in winter, you may have difficulty turning it over. That same phenomenon makes the use of castor lubed fuel inadvisable in very cold weather, you lose part of the lubricant. Additionally, the waxy particles in the fuel can clog the NV, leaning out the engine & robbing it of more lubricant.

Great stuff in warmer weather though.

Good info, guys. As I said before, I bought some castor last night thinking I was going to use it as after-run, but I think I'll go and get some ATF. I'd like to get some MMO air tool oil, if I can find some, but I know without a doubt that ATF will do the chore! Especially as often as I fly my planes....
Thanks

ATF is close to perfect -- it is low viscosity, so that it reaches every nook & cranny, it has sufficient surface tension to stick to the metal parts, it is stable for a loooong time without excess gumming, it burns off cleanly when you light the fire, and it is very cheap and readily available.

Rislone (in the yellow container) is also a good after run oil substitute as is the ATF. Marvel Mystery oil is not to good--no water protection--but Marvel Mystery Air Tool oil (or any air tool oil) is also a good substitute for after run oil. Poor, but better than nothing is sewing machine oil, 3in1 oil or gun oil; all far to thin for after run oil use. Probably the most for the buck is the Rislone.

Air tool oil works best

Mobil One, at 3.49 a quart, it will last for 10 years with me. 100% synthetic motor oil.

I get a quart of benol (racing castor oil) from tower for $5-6 and top off each gallon of fuel with it..about 4 oz and dont use after run oil...all my engines are bushed though and stay inside,,if you have an engine you havent used in 2 years...take it to a swap meet so someone else can!!....Rog

Hi!
Using Castor oil as a after run oil or storage oil is not good.
The reason for this is that Castor oil tends to gum up (oxidize) over time and this will ruin the ball beraings and also make the engine stiff and hard to turn over. A much better way is to use ATF oil or just synthetic auto oil.
For shorter periods (weeks or months) I prefere Castrol DWF spray oil.

Regards!
Jan Karlsson
Sweden

all i can say is there are cheaper alternatives that do a better job.save the castor oil and add it to your fuel,the extra oil will not hurt.i think the oil content is on the low dide these days any way just to keep the cost of fuel down.i remember when oil content was 28%then it went to 25% then 22% then 20% now 18%.fai fuel used to be 75% methanol and 25% castor.